Subsurface sampler



Jan. 13, 1953 c. A. WOFFORD SUBSURF'ACE SAMPLER Filed Dec. 12, 1947 2 SHEETSSHEET l INVENTOR.

BY :04 dv Jan. 13, 1953 C. A. WOFFORD SUBSURFACE SAMPLER Filed Dec. 12, 1947 2 SHEETS-SHEET 2 IN V EN TOR.

ATTORNEYS UNITED STATES OFFICE SUBSURFACE SAMPLER Custer A. Wofford, Tulsa, Okla., assignor to Engineering Laboratories, Inc., Tulsa, Okla., a corporation of Delaware Application December 12, 1947, Serial No. 791,281

1 Claim. 1

This invention relates to a device for obtainin fluid samples and more particularly to a device for obtaining fluid samples from well bores.

In recent years, the petroleum industry has come to a full realization of the importance of Obtaining accurate data regarding hydrocarbonbearing reservoirs. The determination, interpretation, and application of this data is commonly known by the broad term, reservoir engineering.

- 2 subsurface or bottom hole samples of hydrocarbon fluids.

Other objects and advantages of my invention will be apparent upon consideration of the following detailed description of the structure and operation of a preferred embodiment thereof in conjunction with the annexed drawings wherein:

Figure l is a view in vertical section of a sampler constructed in accordance with the teach- Among the data pertinent to reservoir engineerings of the present invention, the valves being ing, are drilling logs, formation sample logs, core shown in open position; records, electrical survey logs, and reservoir fluid Figure la is a view taken along the line Iala characteristics. With these and other data, the in Figure 1; reservoir engineers can predict the future recovw Figure 2 is a view similar to that of Figure 1 cry of hydrocarbon fluids and determine what but illustrating the closed position of the sampler methods of production will recover the maximum valves; q n i y f hy r r n fluid r m h r rv Figure 3 is a view in vertical section of the open In the data enumerated above, the reservoir valve position of the valve operator of the present fluid characteristics are especially useful in preinvention, the assembly of Figure 3 being, in use, dieting the behavior of the fluid ina hydrocarbon th d d t th t of Figures 1 d 2 and lying bearing reservoir, during the productive life of th r ab v the reservoir. It is to be noted that hydrocarbon Figure 4 is a view similar to that of Figure 3 but oil and gas produced at t ace Of the ground showing the closed valve position of the valve has an entirely different set of physical charoperator; acteristics at normal atmospheric pressure and l Figure 5 i i i ti tak along th temperature than the same oil and gas has in li 5-5 of Figure 3; a d the reservoir at super-atmospheric pressure and Figure 6 i a i w in S ti t k along the temperature. Hence, it is very desirable to obtain li 5.45 of Figure 4, fluid p s W ich e truly representative of Referring now more particularly to Figures 1 reservoir conditions. 30 and 2 of the drawings there is shown an elongated While it has been heretofore possible to obtain tubular reservoir chamber 1 having outside 1.. bottom hole samples of hydrocarbon fluids and t0 mensions of approximately 1 and adapted to transfer such samples from the sampler to the contain approximately 650 of fiujd The laboratory for subsequent study, considerable difervoir chamber m is provided at its upper porflculty has been experienced in obtaining a truly 35 tion with a w mechanism l, and in its r representative reservoir sample of hydrocarbon portion with a valve mechanism m both of wh fillid- The device? Which are now available to the are threaded into its wall. Valve mechanisms l I industry for Obtammg bottom hole Samples t and 12 contain valve seats l3 and M respectively "M10115 faults of design and E which which are frustro-conical in shape and which are permit the escape of gas 11qu1d h in coacting relationship with valves l5 and i6 sampler and render the sample of fluid WhlCh 1s respectively ultimately examined non-representative of the The valve Seats '3 and M are provided with 'Y inserts I l and 18 respectively which are made It IS an of my Imentwn to pmvlde of any resilient and readily distortable material sampler so designed as to prevent the escape of ie Another object of my invention is the provision of a sampling device for obtaining representative Eli such as one of the synthetic rubber compounds. This particular type of insert will provide a high ly effective seal. Threaded gasket retainers l9 and 26 hold inserts l1 and -l 8 in place and prevent leakage of fluid between the inserts and valve body assemblies II and [2.

Two different settings of the valve mechanisms l l and i2 are separately shown in Fig. 1 and Fig. 2. In Fig. 1, the valves 15 and it are open thereby allowing the fluid in the drill hole to enter the chamber lfl through the annular opening in the lower valve seat M and to leave the chamber through the opening provided in the upper valve seat i3, thereby insuring thorough flushing as the assembly is lowered through the liquid to be sampled. The motion of the fluid through the chamber is indicated by means of arrows. Fig. 2 shows on the other hand, the valves 15 and IS in a closed position in which they trap any fluids previously introduced into the chamber.

For the operation of the device, means are provided to hold the valves in an open position as shown in Fig. 1, once they are opened, and to hold the valves in a closed position as shown in Fig. 2, once they are closed.

In order to maintain the valves in an open position once they are open, a suitable interlocking mechanism is placed within the chamber Hi. The interlocking mechanism comprises two elongated tubular members. One of these known as interlock sleeve 25, is fixedly connected to the upper. valve 15 by means of a rod 28 and moves upwards or downwards with the valve Fig. 1 shows. the interlock sleeve in the downward position and Fig. 2 shows it in its upward position. The other tubular member in the interlocking mechanism is known as interlock body 21 and is threaded to the lower portion of the chamber is.

The interlock body Zl is comprised of a three (3) pronged tubular member 21a that is internally upset on its upper end. The bottom part of interlock body 2'! is merely a tubular member that is threadedly connected at its lower end to a nut 82 which in turn is threadedly connected to the inside of the sampler chamber it. The nut 82 is provided with a plurality of circumferentially spaced outlets 83 for the passage therethrough of the sample fluid into the chamber Hi. It is apparent that the interlock body 21' is stationary, i. e. it does not. participate in the valve motion.

The interlock mechanism comprises also a third element known as interlock pin 33, which is threadedly connected to the lower valve [6 and is provided with an enlarged end 3|. The interlock pin is contained within. the interlock body and is adapted to move, upwards or downwards with the motion of valve it. Two representative positions of the interlock pin are shown in the drawings. Namely, Fig. 1, illustrates the position whenthe valves are open, and in this position the enlarged end 3i of they interlock pin protrudes through the interlock body 27. When the valves are closed as shown in Fig. 2 the en.- larged. end is maintained in this interlock body 2.1.

The interlock sleeve 25- has a larger diameter than the interlock body 2? and, therefore, is adapted to be shoved down upon the interlock body 21 simultaneously with. the opening of the valves as shown in Fig. 1. The lower portion of the interlock sleeve has a larger internal diam eter than the upper portion, so that when the upper valve is opened the interlock sleeve 25 is forced down over the interlock body ill and, by reason. of the smaller diameter of the upper portion of the sleeve, compresses the tubular pronged interlocking body 2?, thus holding enlarged por tion 3! of the interlock pin against downward movement. Therefore, as long as the upper valve is open the lower valve is held open.

In order to maintain the valves in closed position, a suitable spring mechanism is arranged to cooperate with the valve system. Two nuts 45 and M are provided at suitable distances above the upper valve and below the lowerv valve l6 respectively. These nuts are made fast to the valve by rods 52 and 43 respectively, and serve as seats for one end of compression spring 44 and l5. These compression springs have their other ends pressing against the valve bodies II and [2 respectively, thereby maintaining the valves I5 and i6 normally in a closed position as shown in Fig. 2.

From the above description it can beseen and readily understood that when the lower valve is opened the interlock pin 36, with the enlarged end. 3|, is thus forced upward until the enlargement protrudes above the interlock body 27. Then by opening the upper valve assembly the interlock sleeve 25 is forced down and over the interlock body 2'! and as long as the upper valve is held open the lower valve will also remain open. When the upper valve is allowed to close, through action of the valve spring M, the interlock sleeve 25 will automatically rise and allow the. interlock pin 3! to slip down through the interlock body 2?, and the lower valve spring 45 will thus seat the lower valve.

In order to open and close the. valves at determined instants a suitable energizing means is provided. This means is designated a clock tripping system 58 and is arranged to transmit downwardly upon the nut 40 a force compressing the spring 44 and thereby opening the upper valve, see Figs. 3 to 6 inclusive. This force is transmitted by means of a suitable mechanical linkage positioned Within the housing 5|. Between the clock. tripping mechanism and the housing 51 is interposed a stuiiing box 52, said Stufiing box being threadedly connected to the lower portion of the tripping mechanism andv to theupper portion of the housing.

The clock tripping mechanism comprises a clock 53-, which is of standard tubular construction. The clock is fixedly mounted by any suitable means such as a key to the outer casin of the clock tripping system 56. Within the clock 53 and adapted to rotate therein is a shaft 54 coaxially aligned with the clock 53; The shaft 54-is mounted within the clock 53 by any suitable means obvious to one skilled in the art. To the lower portion of the shaft 54 is attached. a cam 55 adapted to rotatewith the shaft at a uniform angular speed. Below the cam is positioned a trigger 56 which is fastened to a trigger. anchor 51 by means of a suitable hinged pin 53. A trigger spring 59 is provided which tends to. force the trigger to one side. of the. clock tripping chamber. This force is, however, counterbal, anced by the pressure of the cam which is inslidables contact with the upper portion 56a, of the trigger 56. Two relative positions of the cam 55 and trigger element 56a. are illustratedin Figures at which it yields to the spring 56 and causes the trigger to assume an inclined position as shown in Figure 4.

It is therefore apparent that the trigger 55 may occupy two different positions, 1. e., vertical position illustrated in Figure 3, and inclined position. illustrated in Figure 4. Below the trigger 58 is placed a control rod 89 that protrudes downwardly through the stufl'iing box 52 into the linkage system 5i. When the cam is in vertical position as shown in Figure 3, the upper portion of the control rod Bl is held in placel However, during the rotation of the clock, an instant is reached when the-spring 59 causes the trigger to move to the inclined position shown in Figure 4, thereby releasing an appropriate spring mechanism causing the control rod to move upwards as shown in Figure 4.

In operation the internally threaded lower end of the assembly 50 is threaded over the externally threaded boss of the valve seat l3. The control rod 60 is then actuated by the sprin 44 acting through the nut 40, the connected ends of crosshead rods 65 and crosshead BB establishing the connection. It is not necessary that the nut 40 be connected to the ends of the crosshead rods 65 so long as bearing engagement is possible. The two parallel crosshead rods 65 and the crosshead 65 are open to well pressures so that forces due to well pressures by means of being balanced have no effect on the rod 60. The upper end of the rod 60 is under atmospheric pressure only because it is within the clock housing 50 and so protected from well pressure by reason of stufiing box 52. The lower end of rod 60 is also under atmospheric conditions, being contained in a pressure-balancing chamber 80 which is protected from well pressure by stuffing box 8!. Therefore, the only force that can actuate rod 60 is the force of spring 44 tending to close upper valve by reason of pushing up against nut 40, nut 40 in turn, attempting to force the two parallel crosshead rods 65 upward which are connected to rod 50 by means of crosshead 66.

All the structural elements described hereinabove and constituting the present device, are mounted in the form of a single elongated unit adapted to be lowered into a bore hole. The lower portion of this unit is protected by a nose cap 10, having a guard pin 10a, which is threadedly engaged into the lower valve body l2. The upper portion of the unit consists of a tail plug H provided with an opening 12 for receiving a wire line by which the device is lowered into or withdrawn from a well hole. Suitable notches 13 are provided on the external periphery of the tail plug to facilitate recovery of the device in the event that it becomes lost or stuck in the well bore; The tail plug is threadedly connected to the upper portion of the clock housing 50. The joint between the clock housing 50 and tail plug 1 I is sealed with a gasket 14.

In order to understand the operation of my invention let us assume that the device has been assembled and the relative position of the various parts are as shown in Figure 2 with valves closed. In order to obtain a fluid sample, valve [6 must first be opened and held open. This is accomplished by removal of the nose cap 10, having a safety bar Illa. therein, placing the sampler on the ground or some stationary object in a vertical position. The weight of the sampler assembly will open the lower valve l6, and will cause the interlock pin 30 to move upwards until enlarged end of pin 3! is above the top of interlock body 21. The control rod 69 is then pushed down by use of a small pronged tool hooked on top of piston cross head 66 and inserted through opening 84, forcing the upper valve nut 40 downwards and thereby opening the upper valve 15. Simultaneously with the opening of the valve I5, the interlock sleeve 25 is forced down over the interlock body 21 thereby holding the interlock pin 3| in a locked position as explained hereina'bove.

With the valves held thus in an open position, clock head tail plug H is removed, clock 53 is inserted and. turned to the right, or clockwise :until the notch of cam 55 presses against trigger element 56a as shown in Figure 3. The clock is then rotated by hand in the reverse direction at least of a turn, or to the desired time of setting so as to hold trigger 56 vertically and onto the outer circle of the cam. A suitable wire line is then threaded through a stufiing box located in the hoisting apparatus and attached to tail plug H which is then fastened to the top of the clock tripping mechanism housing. The tool which is holding piston crosshead 56 down, is then removed. The cam is then holding trigger 5B vertically which in turn is holding crosshead shaft down, thereby holding upper valve l5 open.

As long as the upper valve is held open the interlock assembly is holding the lower valve open. The nose cap 10 is then fastened to lower valve body l2 to protect lower spring 45. The device is ready to be run into the well.

While lowering the sampler, the well fluids contained within the well enter through the bottom valve which is held open and out through the top valve assuring positive flushing. When predetermined depth is reached the instrument is allowed to set at this depth until a predetermined time has elapsed. When this time has elapsed, the clock will have turned the cam sufficiently to allow the notched portion of the cam to be placed in such a position that the trigger 55 will fall into the notch and against the side of the clock head body, due to the force exerted by spring 59, and will cause an upward thrust of the control rod 50 under the action of spring 44. Consequently, the upper valve 15 closes, raising interlock sleeve 25. This allows the interlock pin 3i to slip down through interlock body 21 and causes the lower valve It to close under theeffect of forces actuated by lower spring 45. Thus a sample of fluid contained in chamber I 0 is sealed.

It will be noted that compression springs 44 and 45 are of such strength as to hold valves i5 and i6 firmly enough on their seats to prevent leakage of fluid from chamber Hl. As valve inserts are resilient and distortable, any solid materials entrained in the well fluid will be depressed into the valve insert by the force of the springs completely sealing the valves. This positive action is highly desirable for obtaining fluid samples from both low and high pressure formations, the spring holding the valves closed when low pressures are encountered and the pressure of the fluid in the chamber forcing the valves tighter on their seats as the device is withdrawn from the well bore and the pressure on the outside of the device decreases. The clock head is positive in its action in holding the valve open, and allowing it to close at a predetermined time is desirable because when taking well samples with a device that depends on the destruction or shearing of some member, it is never known for certain whether this member was destroyed or sheared during descent of the instrument into the bore hole, or when pulled from the bored hole, or if it was sheared or broken at the point desired.

It is to be understood that the form of this invention herewith shown and described is to be taken as a preferred assembly of the same and that various changes in sizes, shape and arrangement of parts may be resorted to without departing from the spirit of this invention as defined by the appended claim.

I claim:

In a sampling device for receiving well fluid samples of the type that includes a casing, a

valve at each end of; said casing, and: means resiliently biasing the saidrvalves to closed position, the. improvement that comprises ahollow interlocking body mounted at one end to said casing, at least a portion of the other end of said body comprising a plurality of pronged', tubular members, said members being internally upset at their upper end, an interlocking. pin attached at one end to one of said valves for slidable movement on the inner surface of said body, said pin having on its other end an enlarged head, a sleeve attached at one end to the other of said valves for 'slidable movement on the outer surface" ofsaid body, said sleeve having a restricted portion at the valve attachment end whereby in. 15

response to the opening of said valves said enlarged head is forced above said pronged,

8 tubular members and. said sleeve looks said pronged,. tubular members. below said head.

CUS'I-ER. A. WOFFORD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS m Number Name Date 2,103,475 Lindsly Dec. 28, 1937 2,147,933 Lindsly Feb. 21 1939 2,161,557 Clark June 6;. 1939 2,265,098 Bettis Dec. 2,. 1941 2,342,367 Pryor Feb. 22,. 1944 2,374,557 Millikan Apr. 24, 1945 2,396,809 Addison Mar. 19, 1946 

